Field of the Invention
The invention relates to the field of conveying members for a conveyor, and in particular to the field of conveying members for an accumulating conveyor. These conveying members include a conveying element, which forms a main surface, and at least one roller mechanism with at least one roller. The invention moreover relates to conveyors that include such conveying members.
Description of Related Art
Such a conveying member is known, for example, from WO 01/32533. A modular belt chain whose modules include a unit that can be retracted relative to the main surface of the modules is described in this document. Here, on the one hand, the unit can project beyond the main surface and, on the other hand, can be arranged flush with the main surface or below this. Amongst other things, the retractable unit can include a roller, which in one embodiment of the retractable unit is freely rotatable and, in another embodiment of the retractable unit, is driven. In a further embodiment, the retractable unit can include rigid drivers. In this manner, the modular belt chain can either convey the conveyed objects on the main surface of the modules in a manner assisted by drivers or also without drivers, on freely rotatable rollers or on driven rollers, depending on the embodiment and the position of the retractable unit.
Such a known module, which can be described as a conveying member, however has the disadvantage that the retractable units take up much space in the retracted condition, by which means the conveying members are not able to be compactly designed.
The described, known conveying member also has the disadvantage that a specific embodiment of the retractable unit is required for each individual change in the type of conveying (with or without drivers, on freely rotatable rollers or not, on driven rollers or not). This results in a cumbersome and complicated design of the conveying member, particularly if more than only two types of conveying are to be possible.
Each change of the type of conveying thus necessitates a specific embodiment of the retractable unit, which moreover must be present on the module in a sufficiently high number in order to be able to fulfil its function. The conveying members therefore need to be provided with a high number of different retractable units, depending on the demands. This also results in a cumbersome and complicated design of the conveying member.
A complete retraction of the retractable module can result in long paths between the retracted position of the retractable module and the non-retracted position. Due to large distances between both positions, the retractable module can only be moved slowly between the two positions or however rapidly and amid a high material loading.
The cumbersome and complicated design of the conveying member entails high costs on manufacture, maintenance and repair. Cumbersome and complicated designs are moreover prone to wear and defects.
A cumbersome and complicated design of the conveying member moreover results in a high weight of the conveying member in the case of a robust embodiment and this leads to high energy consumption on moving the conveying member.